U.S. Pat. No. 4,963,444 A and U.S. Pat. No. 5,096,787 A disclose a lead-acid battery having a housing which is subdivided into a plurality of cell areas. Electrolyte plate stacks containing lead are held in the cell areas and are separated from one another by separators. Furthermore, the cell areas are filled with liquid electrolyte which, in particular, contains sulfuric acid.
During operation, the acid concentration may be distributed non-uniformly over the height of the rechargeable battery, thus leading to a reduction in the storage capacity of the rechargeable battery. It is therefore desirable to mix the liquid electrolyte during operation. For this purpose, a hydrostatic pump is created by wall elements adjacent to side walls of the rechargeable battery housing. When the rechargeable battery moves, electrolyte sloshes over the upper edge of the walls into the volume area bounded by a wall, as a result of which the electrolyte level in this volume area is higher than in the adjacent volume area. During movement, electrolyte additionally flows through an opening in the lower area into the volume area bounded by the wall elements. The electrolyte level, which is now higher in this volume area, leads to a hydrostatic overpressure in the volume area, as a result of which electrolyte flows away again out of the overfilled volume area into the adjacent volume area. The hydrostatic pump therefore ensures that a circulating electrolyte movement occurs.
The circulating electrolyte movement has the disadvantage, however, that sludge and particles deposited in the lower area are picked up and are moved into the area above the separators. This increases the risk of short-circuiting.
U.S. Pat. No. 529,199 discloses a rechargeable battery system in which fluid is caused to circulate by means of a pump device. In one embodiment, rechargeable batteries are mounted on a rocker in order to use outlet elements and grooves to ensure that the electrolyte circulates.